UNIT 3 NOTES:Heart Anatomy

& Basic Function

(1) Cardiac Tissues• Outermost = Pericardium & Epicardium

– Pericardium is a membrane anchoring heart to diaphragm and sternum

– Pericardium secretes lubricant (serous fluid)– Epicardium is outermost muscle tissue

• Middle = Myocardium– Contains contractile muscle fibers

• Innermost = Endocardium– Lines Cardiac Chambers

(2) The Chambers• Human heart has 4 chambers

– 2 Atria (1 on the left, 1 on the right)• Superior Chambers = Primary Receiving Chambers

(do not actually pump)• Blood flows into atria

– 2 Ventricles (1 on the left, 1 on the right)• Inferior Chambers = Pump the Blood• Contraction = blood sent out of heart + circulated

• Chambers are separated by septum

Deoxygenated Blood

…To the lungs

Oxygenated Blood

…To the rest of the body

(3) Pulmonary Circulation• Pulmonary = Deoxygenated Blood

• Involves Right Side of Heart

• Pathway:Pathway:1. Superior / Inferior Vena Cava

2. Right Atrium Tricuspid Valve

3. Right Ventricle Pulmonary Semilunar Valve

4. Left Pulmonary Artery

5. Lungs

(4) Systemic Circulation• Systemic = Oxygenated Blood

• Involves Left Side of Heart

• Pathway:Pathway:1. Left Pulmonary Vein

2. Left Atrium Bicuspid Valve

3. Left Ventricle Aortic Semilunar Valve

4. Aorta

5. All Other Tissues

(5) The Valves• The AV Valves:

– AV = atrioventricular = between the atrium and ventricles– Tricuspid Valve

• Right Side– Bicuspid / Mitral Valve

• Left Side

• The Semilunar Valves:– Semilunar = between the ventricles and arteries exiting the heart– Pulmonary Semilunar Valve

• Right Side• Exiting out the pulmonary artery going to the lungs.

– Aortic Semilunar Valve• Left Side• Exiting out the aorta going to working tissues.

(6) The Valves & Heart Pumping

• When the heart is relaxed…– Blood passively fills atrium– Flows right past tricuspid / bicuspid valves– Semilunar Valves remain shut

• When the heart contracts (pumps)…– Tricuspid / Bicuspid valves swing up and shut– Blood ejected out of ventricle– Semilunar Valves open up